CN106464027B

CN106464027B - Method and system for object detection and sensing for wireless charging systems

Info

Publication number: CN106464027B
Application number: CN201580031659.6A
Authority: CN
Inventors: A·加西亚布利兹; A·M·吉尔伯特; G·奥姆巴赫
Original assignee: Qualcomm Inc
Current assignee: WiTricity Corp
Priority date: 2014-06-17
Filing date: 2015-06-10
Publication date: 2020-05-19
Anticipated expiration: 2035-06-10
Also published as: EP3140149A1; WO2015195442A1; JP2017528097A; EP3140149B1; CN106464027A; US20150364944A1; KR102423980B1; US9735605B2; KR20170017922A

Abstract

An apparatus and method for detecting conditions within a wireless charging field is described. In one embodiment, an apparatus includes a wireless power receiver configured to receive wireless charging power from a wireless power charging transmitter. The apparatus further includes a first sensor circuit disposed at least partially within the ground surface, the first sensor operatively coupled to the wireless power receiver and configured to be charged or powered by the wireless power receiver. The first sensor is further configured to detect a condition.

Description

Method and system for object detection and sensing for wireless charging systems

Technical Field

The present disclosure relates generally to wireless power. More particularly, the present disclosure is directed to devices, systems, and methods related to foreign object detection and sensor integration for wireless power transfer systems.

Background

Wireless power transfer systems may differ in many respects, including circuit topology, magnetic layout, and power transfer capability or requirements. The amount of power transferred between components of the wireless charging system may be affected by foreign objects near the primary charging pad, further leading to safety concerns related to the heating of such foreign objects. Accordingly, there is a need in the art to improve detection of the presence of foreign objects between the primary charging pad and the electric vehicle.

Disclosure of Invention

An apparatus for detecting a condition within a wireless charging field is provided. The apparatus includes a wireless power receiver configured to receive wireless charging power from a wireless power charging transmitter. The apparatus further includes a first sensor circuit disposed at least partially within the ground surface. The first sensor is operatively coupled to the wireless power receiver and configured to be charged or powered by the wireless power receiver and further configured to detect a condition.

A method for detecting a condition within a wireless charging field is provided. The method comprises the following steps: wireless charging power is received at a wireless power receiver from a wireless power charging transmitter. The method further comprises the following steps: a condition is detected at a first sensor circuit, the first sensor circuit being at least partially disposed within the ground surface, operatively coupled to, and charged or powered by, the wireless power receiver.

An apparatus for detecting a condition within a wireless charging field is provided. The apparatus includes means for receiving wireless charging power from a wireless power charging transmitter. The apparatus further includes a first component for detecting a condition. The first detection component is disposed at least partially within the ground surface and is operatively coupled to and charged or powered by the receiving component.

An apparatus for providing wireless power is provided. The apparatus includes a wireless power transmitter configured to provide wireless power to the first sensor circuit. The apparatus further includes a first controller configured to receive information from the first sensor circuit. The information indicates the presence of a foreign object. The first controller is further configured to reduce power transmitted from the wireless power transmitter to the electric vehicle in response to the information.

Drawings

Fig. 1 is a functional block diagram of a wireless power transfer system according to an example embodiment.

Fig. 2 is a functional block diagram of a wireless power transfer system according to another example embodiment.

Fig. 3 is a schematic diagram of a portion of the transmit or receive circuitry of fig. 2 including a transmit or receive antenna, according to an example embodiment.

Fig. 4 is a diagram of a vehicle aligned above a transmitter coil according to another exemplary embodiment of a stationary wireless charging system.

Fig. 5 is a perspective view of an electric vehicle traveling along a roadway above a wireless power transfer system, according to another exemplary embodiment of a dynamic wireless charging system.

Fig. 6A is a functional block diagram of a wireless power transfer system according to an example embodiment.

Fig. 6B is a functional block diagram of a sensor of a wireless power transfer system, according to an example embodiment.

Fig. 7A is a side view of a wireless power transfer system with multiple sensors, according to an example embodiment.

Fig. 7B is a top view of the wireless power transfer system of fig. 7A, according to an example embodiment.

Fig. 8 illustrates a flow chart depicting a method of providing wireless power to the sensor of fig. 7A or 7B, according to an example embodiment.

FIG. 9 illustrates a flow chart depicting a method of operating one or more of the sensors according to an exemplary embodiment.

Detailed Description

The detailed description set forth below in connection with the appended drawings is intended as a description of certain embodiments of the present invention and is not intended to represent the only embodiments in which the present invention may be practiced. The term "exemplary" as used throughout this description means "serving as an example, instance, or illustration," and should not necessarily be construed as preferred or advantageous over other exemplary embodiments. The detailed description includes specific details for the purpose of providing a thorough understanding of the disclosed embodiments. In some instances, some devices are shown in block diagram form.

Wireless power transfer may refer to the transfer of any form of energy associated with an electric field, magnetic field, electromagnetic field, or other aspect from a transmitter to a receiver without the use of physical electrical conductors (e.g., power may be transferred through free space). The power output into a wireless field (e.g., a magnetic or electromagnetic field) may be received, captured, or coupled by a "receive antenna" to enable power transfer.

A Foreign Object Detection (FOD) sensor integrated with a primary charging pad of an Inductive Power Transfer (IPT) system may be implemented as a sensing pad integrated with the primary charging pad or as an individual sensor placed on the surface of the pad. Therefore, it is desirable to improve FOD resolution when the primary charging pad is mounted within or below the ground.

Fig. 1 is a functional block diagram of a wireless power transfer system 100 according to an example embodiment. Input power 102 may be provided to a transmitter 104 from a power source (not shown) to generate a wireless (e.g., magnetic or electromagnetic) field 105 for performing energy transfer. The receiver 108 may be coupled to the wireless field 105 and generate output power 110 for storage or consumption by a device (not shown) coupled to the output power 110. Both the transmitter 104 and the receiver 108 are separated by a distance 112.

In an exemplary embodiment, the transmitter 104 and the receiver 108 are configured according to a mutual resonant relationship. Transmission losses between the transmitter 104 and the receiver 108 are minimized when the resonant frequency of the receiver 108 and the resonant frequency of the transmitter 104 are approximately the same or very close. As such, wireless power transfer may be provided over greater distances, in contrast to purely inductive solutions that may require large antenna coils that are very close (e.g., sometimes within a few millimeters). Resonant inductive coupling techniques may thus allow improved efficiency and power transfer over various distances and with various inductive coil configurations.

The receiver 108 may receive power when the receiver 108 is located in the wireless field 105 generated by the transmitter 104. The wireless field 105 corresponds to a zone (region) in which energy output by the transmitter 104 can be captured by the receiver 108. As will be described further below, the wireless field 105 may correspond to the "near field" of the transmitter 104. The transmitter 104 may include a transmit antenna or coil 114 for transmitting energy to the receiver 108. The receiver 108 may include a receive antenna or coil 118 for receiving or capturing energy transmitted from the transmitter 104. The near field may correspond to a zone in which there is a strong reactive field (reactive field) created by the currents and charges in the transmit coil 114 that minimally radiate power away from the transmit coil 114. The near-field may correspond to a zone within about one wavelength (or a fraction thereof) of the transmit coil 114.

As described above, efficient energy transfer can occur by coupling most of the energy in the wireless field 105 to the receive coil 118 rather than propagating most of the energy in the electromagnetic wave to the far field. When positioned within the wireless field 105, a "coupling mode" may form between the transmit coil 114 and the receive coil 118. The area (area) around the transmit antenna 114 and the receive antenna 118 where this coupling can occur is referred to herein as a coupling-mode region.

Fig. 2 is a functional block diagram of a wireless power transfer system 200 according to another example embodiment. The system 200 includes a transmitter 204 and a receiver 208. The transmitter 204 may include transmit circuitry 206, and the transmit circuitry 206 may include an oscillator 222, a driver circuit 224, and a filtering and matching circuit 226. The oscillator 222 may be configured to generate a signal at a desired frequency, which may be adjusted in response to the frequency control signal 223. The oscillator 222 may provide an oscillator signal to the driver circuit 224. Driver circuit 224 may be configured to drive transmit antenna 214 at, for example, a resonant frequency of transmit antenna 214 based on input voltage signal (VD) 225. The driver circuit 224 may be a switching amplifier configured to receive a square wave from the oscillator 222 and output a sine wave. For example, the driver circuit 224 may be a class E amplifier.

The filtering and matching circuit 226 may filter out harmonics or other unwanted frequencies and match the impedance of the transmitter 204 to the transmit antenna 214. As a result of driving transmit antenna 214, transmit antenna 214 may generate wireless field 205 to wirelessly output power at a level sufficient for charging a battery 236 of, for example, an electric vehicle.

The receiver 208 may include a receive circuit 210, and the receive circuit 210 may include a matching circuit 232 and a rectifier circuit 234. The matching circuit 232 may match the impedance of the receive circuit 210 to the receive antenna 218. As shown in fig. 2, the rectifier circuit 234 may generate a Direct Current (DC) power output from an Alternating Current (AC) power input to charge the battery 236. The receiver 208 and transmitter 204 may additionally communicate over a separate communication channel 219 (e.g., bluetooth, Zigbee, cellular, etc.). The receiver 208 and transmitter 204 may alternatively communicate via in-band signaling using characteristics of the wireless field 205.

The receiver 208 may be configured to determine whether the amount of power transmitted by the transmitter 204 and received by the receiver 208 is suitable for charging the battery 236.

Fig. 3 is a schematic diagram of a portion of the transmit circuitry 206 or receive circuitry 210 of fig. 2 including a transmit or receive antenna, according to an example embodiment. As illustrated in fig. 3, transmit or receive circuitry 350 may include an antenna 352. The antenna 352 may also be referred to or configured as a "loop" antenna 352. The antenna 352 may also be referred to or configured as a "magnetic" antenna or induction coil herein. The term "antenna" generally refers to a component that may wirelessly output or receive energy for coupling to another "antenna". The antenna may also be referred to as a coil of a type configured to wirelessly output or receive power. As used herein, antenna 352 is an example of a "power transfer component" of a type that is configured to wirelessly output and/or receive power.

The antenna 352 may include an air core or a physical core, such as a ferrite core (not shown). Air core loop antennas may be more tolerable to foreign physical devices placed near the core. In addition, the air core loop antenna 352 allows other components to be placed within the core region. In addition, the air core loop may more easily enable the receive antenna 218 (fig. 2) to be placed in the plane of the transmit antenna 214 (fig. 2), where the coupling-mode region of the transmit antenna 214 may be more powerful.

As stated, efficient transfer of energy between the transmitter 104/204 and the receiver 108/208 may occur during matching or nearly matching resonances between the transmitter 104/204 and the receiver 108/208. However, even when the resonance between the transmitter 104/204 and the receiver 108/208 is not matched, energy may be transferred, but efficiency may be affected. For example, efficiency may be lower when the resonances are mismatched. The transfer of energy occurs by coupling energy from the wireless field 105/205 of the transmit coil 114/214 to the receive coil 118/218 present in the vicinity of the wireless field 105/205, rather than propagating energy from the transmit coil 114/214 into free space.

The resonant frequency of a loop antenna or magnetic antenna is based on inductance and capacitance. The inductance may simply be the inductance created by the antenna 352, and the capacitance may be added to the inductance of the antenna to create a resonant structure at the desired resonant frequency. As a non-limiting example, a capacitor 354 and a capacitor 356 may be added to the transmit or receive circuit 350 to create a resonant circuit that selects a signal 358 at a resonant frequency. Thus, for larger diameter antennas, the size of the capacitance required to maintain resonance may decrease as the diameter or inductance of the loop increases.

Furthermore, as the diameter of the antenna increases, the efficient energy transfer area of the near field may increase. Other resonant circuits formed using other components are also possible. As another non-limiting example, a capacitor may be placed in parallel between two terminals of circuit 350. For a transmitting antenna, a signal 358 having a frequency that approximately corresponds to the resonant frequency of the antenna 352 may be an input to the antenna 352.

Referring to fig. 1 and 2, transmitter 104/204 may output a time-varying magnetic (or electromagnetic) field having a frequency corresponding to the resonant frequency of transmit coil 114/214. When the receiver 108/208 is within the wireless field 105/205, the time-varying magnetic (or electromagnetic) field may induce a current in the receive coil 118/218. As described above, energy may be efficiently transferred if the receive coil 118/218 is configured to resonate at the frequency of the transmit coil 114/214. The AC signal induced in the receive coil 118/218 may be rectified as described above to produce a DC signal that may be provided to charge or power a load.

Fig. 4 is a diagram of a vehicle aligned above a transmitter coil according to an exemplary embodiment of a stationary wireless charging system. The stationary wireless power transfer system 400 enables charging of the vehicle 405 when the vehicle 405 is parked near the transmitter 404. A space for a vehicle 405 to be parked over a transmit coil 414 (similar to transmit coils 114/214) is shown. The transmit coil 414 (shown in phantom) may be located within the base pad 415 (shown in phantom). In some implementations, the transmitter 404 may be connected to a power backbone 410 (e.g., a power grid). The transmitter 404 may be configured to provide Alternating Current (AC) through an electrical connection 420 to a transmit coil 414 located within the base pad 415. The vehicle 405 may include a battery 424, a receive coil 418 (similar to receive coils 118/218), and an antenna 427, each connected to the receiver 408.

In some implementations, the receive coil 418 can receive power when the receive coil 418 is in a wireless (e.g., magnetic or electromagnetic) field generated by the transmit coil 414. The wireless field corresponds to a zone where energy output by the transmit coil 414 can be captured by the receive coil 418. In some cases, the wireless field may correspond to the "near field" of the transmit coil 414.

Foreign object 430 is also shown near base pad 415 and transmitter coil 414. Foreign object 430 may include any object that is not part of the wireless charging system and/or is not intended to be present during the charging process between transmit coil 414 and receive coil 418. For example, in an embodiment of the wireless charging system 500 implemented in a garage, the foreign object 430 may be a tool (e.g., a wrench, a hammer, etc.).

The foreign object 430 may cause several problems for the wireless charging system 400. The foreign object 430 may interfere with the charging process by distorting the near field of the transmit coil 414, reducing the efficiency of the system, or completely interrupting the charging. Foreign object 430 may absorb energy from transmitting coil 414, posing a heating or fire hazard to both system 400 and to bystanders. Where the foreign object 430 is a metal object (e.g., a wrench), these problems may be magnified, particularly where the foreign object 430 is ferromagnetic. As mentioned, the effectiveness of the overall system may be adversely affected by the presence of foreign object 430, and therefore a sensor for detecting foreign object 430 is desirable. Certain embodiments of such sensors are disclosed and described below in the following figures.

Fig. 5 is a perspective view of an electric vehicle traveling along a roadway over a wireless power transfer system, according to another exemplary embodiment of a dynamic wireless charging system. The electric vehicle 505 is traveling along the lane on the left side in a lane that passes sequentially over each of the four charging mats 515a-515d of the dynamic wireless charging system 500. The electric vehicle 505 is traveling along the roadway 525 from the bottom to the top of the page across each of the four charging base pads 515a-515d, which are positioned linearly from end to end along the center of the left lane 526. The charging base pad 515a is the first of four that are passed by the electric vehicle 505. The left lane 526 may also include one or more proximity devices 510a-510c located in and around the vicinity of the charging mats 515a-515 d. The system 500 may include proximity devices 510a-510c to provide an indication to the system 500 that the vehicle 505 is approaching. In response to the presence of the vehicle 505, the proximity device may alert an Electric Vehicle Support Equipment (EVSE)520, which EVSE 520 may command activation or deactivation of the charging base pads 515a-515 d. As shown in fig. 5, activation of the charging base pads 515a-515d may be done in sequence to provide wireless power to the vehicle 505.

The EVSE may include a plurality of electronic components and processors (such as those discussed below with respect to fig. 6A) configured to communicate with the vehicle 505 and control the operation of the dynamic wireless charging system 500. The EVSE 520 may provide control signals to a controller (not shown) that may provide signals to activate or deactivate the charging base pads 515a-515d and the entire charging process of the wireless charging system 500. As will be discussed in fig. 6A, the controller may receive input and provide specific commands to the charging base pads 515a-515 d.

The EVSE 520 may be electrically connected (not shown) to each of the charging base pads 515a-515d and the proximity devices 510a-510c to receive and process charging requests from passing electric vehicles 505 on the roadway 525. The EVSE 520 may also broadcast the services of the dynamic wireless charging system 500 to passing electric vehicles 505. The EVSE 520 may control the charging process of the system 500, determining whether the electric vehicle 605 is permitted to receive charging from the charging base pads 515a-515 d.

If it is determined that the electric vehicle 505 is allowed to receive charging, the EVSE 520 can provide additional communication or visual indicators (not shown in this figure) to the electric vehicle 505, or to an operator therein, regarding the alignment of the electric vehicle 505 along the width of the roadway 525.

The EVSE 520, and more particularly a controller (not shown), may utilize information from the proximity sensors 510a-510c regarding the proximity of the electric vehicle 505 to sequentially energize and de-energize the charging basepads 515a-515d in response to the presence (or absence) of the vehicle 505. The dynamic charging system 500 may include the EVSE 520, the vehicle 505, and communications between at least the proximity sensors 510a-510c and the charge pads 515a-515d to provide wireless power transfer to the vehicle 505.

FOD is an additional concern in the embodiment depicted in fig. 4 because the roadway 525 is open to contamination from objects falling from passing traffic or otherwise being blown or dropped into the roadway 525. As shown in fig. 5,

foreign objects

530a, 530b may be present on the roadway 525, adversely affecting the transfer of power from the charge pads 515a-515d to the charging system of the vehicle 505. Similar to the stationary wireless charging system 400, the presence and/or type of foreign object 530 (e.g., a metal or ferromagnetic object) may also present a road hazard or heating hazard.

Fig. 6A is a functional block diagram of a wireless power transfer system 600 according to an example embodiment. System 600 includes a transmitter 604 and a receiver 608. As shown in fig. 6A, transmitter 604 may include a communication circuit 629 electrically connected to transmit circuit 606. The transmit circuit 606 may include an oscillator 622, a driver circuit 624, and a filtering and matching circuit 626. Oscillator 622 may be configured to generate a signal at a desired frequency, which may be adjusted in response to frequency control signal 623. The oscillator 622 may provide an oscillator signal to a driver circuit 624. The driver circuit 624 may be configured to drive the transmit antenna 614 at, for example, a resonant frequency of the transmit antenna 614 based on the input voltage signal (VD) 625. In one non-limiting example, the driver circuit 624 may be a switching amplifier configured to receive a square wave from the oscillator 622 and output a sine wave.

The filtering and matching circuit 626 may filter out harmonics or other unwanted frequencies and match the impedance of the transmitter 604 to the transmit antenna 614. As a result of driving the transmit antenna 614, the transmit antenna 614 may generate the wireless field 605 to wirelessly output power at a level sufficient for charging a battery 636 of, for example, an electric vehicle. Unless otherwise stated, each component within transmit circuitry 606 may have substantially the same functionality as the corresponding component within transmit circuitry 206 as previously described with respect to fig. 2.

The transmitter 604 may further include a controller circuit 628 electrically connected to the communication circuit 629. The communication circuitry 629 may be configured to communicate with the communication circuitry 639 within the receiver 608 over a communication link 619. Communication from the transmitter 604 to the receiver 608 via the communication link 619 may include information regarding the charging process, including increased or decreased power capabilities of the transmitter 604 and other information associated with the charging capabilities of the transmitter 604.

The receiver 608 may include a receive coil 618 and receive circuitry 610. The receive circuit 610 may include a switch circuit 630 connected to a matching circuit 632, and a rectifier circuit 634 connected to the matching circuit 632. The receive coil 618 may be electrically connected to a switching circuit 630. The switching circuit may selectively connect the receive coil 618 to the matching circuit 632 or to connect the short-circuited terminals of the receive coil 618 together. The matching circuit 632 may be electrically connected to the rectifier circuit 634. The rectifier circuit 634 may provide a DC current to the battery 636. Unless otherwise stated, each component within receive circuitry 610 may have substantially the same functionality as the corresponding component within receive circuitry 210 as previously described with respect to fig. 2.

The receiver 608 may further include a sensor circuit 635, the sensor circuit 635 configured to sense a short circuit current or an open circuit voltage of the receive coil 618. The controller circuit 638 may be electrically connected to the sensor circuit 635 and receive sensor data from the sensor circuit 635. The communication circuit 639 may be connected to the controller circuit 638. The communication circuitry 639 may be configured to communicate with the communication circuitry 629 within the transmitter 604 via a communication link 619 (similar to those mentioned above). Such communication may be used to indicate to the transmitter 604 the specific power requirements of the receiver 608, the state of charge of the battery 636, or other information related to the power requirements of the receiver 608.

To provide power from the transmitter 604 to the receiver 608, energy may be transmitted from the transmit coil 614 to the receive coil 618 through a wireless field (e.g., a magnetic or electromagnetic field) 605. The transmit coil 614 and the transmit circuit 606 form a resonant circuit having a particular resonant frequency. The receive coil 618 and the receive circuit 610 form another resonant circuit having a particular resonant frequency. Because electromagnetic losses are minimized between two coupled resonant systems having the same resonant frequency, it is desirable for the resonant frequency associated with receive coil 618 to be approximately the same as the resonant frequency associated with transmit coil 614. Therefore, it is further desirable that the tuning topology for one or both of the transmit coil 614 and the receive coil 618 not be significantly affected by inductance or load changes.

In accordance with the above description, the controller circuit 638 may determine the maximum possible output current or voltage for any position of the receive coil 618 with respect to the transmit coil 614. The controller circuit 638 may make this determination before supplying current to the battery 636. In another embodiment, the controller circuit 638 may make such a determination during charging of the battery 636. Such embodiments may provide a safety mechanism to ensure that the charging current and/or voltage remains within safe limits during the charging cycle. In yet another embodiment, the controller circuit 638 may make this determination when the driver of the vehicle 405 is driving the vehicle 405 (fig. 4) into a space for charging, or when the proximity sensors 510a-510c of the system 500 (fig. 5) detect the presence of the vehicle 505.

As mentioned above, the tuning topology of the wireless charging system 600 may be adversely affected by the presence of foreign objects (e.g., foreign object 430 of fig. 4,

foreign objects

530a, 530b of fig. 5). When the foreign objects 430, 530 are metallic, they may interfere with the wireless field 605 by reducing, distorting, or absorbing the wireless field 605 and disrupting power transfer from the transmit coil 614 to the receive coil 618. Thus, in certain embodiments, the wireless charging system 600 may further include one or more sensors 650a-650d arranged in a distributed network (e.g., an array) proximate to the transmitter 604. The sensors 650a-650d may be collectively referred to herein as sensors 650. The four sensors 650 shown should not be considered limiting; any number of sensors may be implemented without departing from the spirit of the present disclosure. In one embodiment, each of the sensors 650a-650d may be distributed around or over the individual emitters 604. The precise placement of such sensors 650 is described further below. Furthermore, the sensor 650 may be employed in a stationary wireless charging system as mentioned with respect to fig. 4 or in a dynamic wireless charging system as mentioned with respect to fig. 5.

The sensors 650a-650d may include temperature sensors, Infrared (IR) sensors, microwave, millimeter wave, LIDAR (e.g., light detection and ranging or light radar) sensors, or other applicable sensors for use in the detection of foreign objects in the vicinity of the emitter 604. As shown, sensor 650a may be a thermistor, sensor 650b may be a thermal (IR) camera, sensor 650c may be a radar sensor, and sensor 650d may be an imaging camera. As shown, the sensor 650a may provide information to the controller 628 related to temperature. If the foreign object 430, 530 is near the transmitter 604, it may absorb energy from the wireless field 605 and thus increase in temperature. An increase in temperature (e.g., a local increase in temperature) measured by the sensor 650a may indicate the presence of the foreign object 430, 530.

The sensor 650b may provide a thermal (e.g., IR) image of the area around the sensor 650b and may provide visual detection of foreign objects 430, 530. In one embodiment, the sensor 650b may provide confirmation of another detection by the proximity sensor 650 even at night or in reduced visibility. Because IR energy is emitted from the object as it is heated, the foreign object 430, 530 may become detectable by the sensor 650b as it absorbs energy from the emitter 604.

The camera of the sensor 650d may provide similar capabilities as the sensor 650b that independently detects or provides visual confirmation of different detections of foreign objects 430, 530. The sensor 650c may include a radar sensor (e.g., millimeter wave radar, LIDAR, etc.) that provides electronic components to detect the foreign object 430, 530 (or confirm detection of the foreign object 430, 530). Each of the sensors 650 may communicate sensor information to the transmitter 604 (and more particularly the controller 629) via the communication circuitry 629.

These specific examples of sensors 650 should not be considered limiting, as each of the sensors 650 may include at least one sensor, but may also include various capabilities to increase the overall effectiveness of the sensor array. The choice of sensor type may depend on environmental and design factors as well as system capabilities. Depending on the particular implementation, other capabilities such as air quality or air pollution sensors (e.g., particle sensors, or nitrogen oxide (NOx) sensors) are also contemplated, in addition to other environmental conditions such as humidity. NOx compounds include a wide variety of compounds in the atmospheric chemistry generated by the combustion process (e.g., NO)₂) They are considered harmful to human health.

In an embodiment, the sensor 650 may be further configured to detect an unexpected change in the emitted field 605, which may indicate the presence of a foreign object 430, 530 absorbing energy of the field 605, or an object independently generating another electromagnetic signal or wireless power.

The placement of the sensor near the transmitter 604 may depend on the capabilities of the sensor 650 and the design requirements of the system 600. Each of the sensors 650 may provide information related to the presence of a foreign object (e.g., foreign object 402, 630a, 630b), or other information pertaining to an environmental or road condition. This information may be transmitted to and/or used by other systems and subsystems (e.g., transmitter 604) to inform a driver within vehicle 505 of the charging condition, FOD, or road condition (among other available information). In one embodiment, the sensor may indicate a degraded mode of the transmitter 604, such as a road warning, in the case of a large object or a reduced transmit power level from the coil 614 in the presence of a smaller object.

As shown, sensors 650a-650c may be wireless sensors having wireless communication with communications circuitry 629 via

links

652a, 652 b. The communication from the sensor 650 to the controller 628 may include a foreign object detection signal prompting the controller 628 to adjust the wireless power output of the transmitter 604.

The sensor 650a is further shown in the near field of the wireless field 605. As such, the sensor 650a may receive wireless power from the transmit coil 614. It will be appreciated that each of the wireless sensors 650a-650c may be capable of receiving wireless power from the transmitter 604; however, for simplicity, this is not shown in fig. 6A. The distributed and wireless power capability of the sensor 650 results in a modular and customizable FOD system that allows for easier maintenance and replacement of components.

In one embodiment, each of the sensors 650a-650c may alternatively or additionally be equipped with a power storage device, such as a battery (not shown). The ability to wirelessly or independently power each of the sensors 650a-650c (e.g., a battery) enables simplified maintenance, replacement, and/or addition and removal of individual sensors 650.

Sensor 650d is shown with a wired link 654 to transmitter 604. The transmitter 604 provides a wired link 654 to the sensor 650d to enable communication with the transmitter 604 and power to operate. In addition to communication with the transmitter 604, each of the sensors 650a-650d may further have inter-sensor communications 656a-656b, wired or wireless, between each other. The sensors 650a-650d may further be equipped with enhanced communicationCapability to communicate via, for example, Bluetooth^TMInter-sensor communication 656 of WiFi (e.g., 802.11), etc., or further acts as a relay node or relay nodes for vehicle-to-pad (V2P), vehicle-to-grid (V2G), vehicle-to-infrastructure (V2I), or vehicle-to-vehicle (V2V) communication to relay sensor information to and from proximity sensors 650, controllers 628, or electric vehicles 505 (of fig. 5). By way of non-limiting example, V2P communication may occur from vehicle 505 to communication circuit 629 (and controller 628); V2G communication may occur between vehicle 505 and grid or backbone 410 (fig. 4); V2I communication may occur from vehicle 505 to infrastructure (e.g., a network other than the grid); and V2V communication may occur between two vehicles 505. In each of the noted examples, the sensor 650 may transmit sensor information between the various components of the wireless

power transfer systems

500, 600 using a wireless communication link 656 or a wired communication link 654.

In one embodiment, the inter-sensor communication 656 or the communication via link 652 may further include a proprietary or encrypted communication protocol. Such a protocol may have a short range (e.g., 5-10 meters) for the networked sensors 650. The V2I, I2V, and V2V communications may be further tunneled so that information related to road conditions, traffic and accidents, or weather, etc. may be transmitted directly to electric vehicles 605 that are not in direct communication with a given transmitter 604 or system 600. As a non-limiting example, V2I communication and a reverse path (infrastructure-to-vehicle (I2V) communication) can follow the path "vehicle-sensor-EVSE-infrastructure" in both directions, with the sensor 650 acting as a link between the vehicle 505 and the EVSE 520. In one embodiment, this makes communications available anywhere on the road 525 with the wireless power transfer system 600, and is therefore not limited, such as via bluetooth^TMWiFi, and other short-range communication systems.

A sensor 650 that detects the presence of a nearby foreign object may transmit a detection signal to the controller circuit 628 via the communication circuit 629 (e.g., via

links

652a, 652b or wired link 654). The sensor 650 detecting the foreign object may alternatively relay the detection signal to the communication circuit 629 and the controller 628 through another sensor 650. The controller circuit 628 may then alter the transmission characteristics of the transmitter 604 (as a whole) in response to the FOD detection signal by commanding the transmit circuit 606 to adjust (e.g., increase or decrease) the power output of the transmitter coil 614. The presence of foreign objects near transmitter 604 may present a hazard to charging system 600 and to vehicle 605 driving on the road. Accordingly, the controller 628 may reduce the power output of the transmitter 604 or stop the charging operation altogether in response to the presence of the foreign object 430, 530. This may reduce hazards (e.g., fire) associated with heating of the foreign objects 430, 530, and may also provide a warning indicating the presence of an object in the near field of the transmitter coil 614, which may otherwise reduce the efficiency of the system 600 or pose a road hazard to vehicles (e.g., electric vehicles 605) in the roadway 525.

The ability of the sensors 650 to communicate with each other and relay information may also increase the flow of information from the various sensors 650 to the transmitter 604. In one embodiment, the sensors 650 may further communicate directly with the

vehicles

505, 405 to relay such information.

In another embodiment, the detection by the sensor 650 may ultimately result in the following warning to the operator of the vehicle 505: foreign objects 530 are present in the road 525, which may be dangerous to the motorist. In a residential setting where a wireless charging system (e.g., system 400) may be installed (e.g., in a garage), the sensor 650 may provide the homeowner with a warning as follows: the risk of fire due to the presence of foreign object 430. In embodiments incorporating other mentioned environmental sensors, additional data relating to weather, road, or traffic conditions may be made available to the driver of the vehicle 505, in addition to other useful data. Information obtained from the sensors 650 may be communicated to the transmitter 604 and forwarded to the grid (e.g., backbone 410 or V2G communication of fig. 4), vehicle (e.g., V2P), or other proximate dynamic charging system 600.

In one embodiment, the type of sensor employed as sensor 650 (e.g., IR, thermal camera, thermistor, radar, etc.) may affect the actions commanded by controller 628. As a non-limiting example, if a thermistor is employed as the sensor 650a, then only the temperature may be reported to the transmitter 604. In one embodiment, the high temperature reading from sensor 650a may result in a modification of the charging process of system 600 as mentioned above. Alternatively, a very high temperature reading from sensor 650a, or an indication from sensor 650b that a large piece of metal is present near the transmitter coil 614 may result in a complete shutdown of the charging process. The temperature threshold governing such functionality may vary based on a number of characteristics, such as system architecture (e.g., sensor placement), foreign object 630 type (if determined), and power output, among other possibilities.

The controller 628 may adapt the specific power adjustment command to the coil 614 according to various conditions, such as the type of sensor 650, the power output of the system 600, the size and location of the foreign object, among other characteristics. Advantageously, the sensor 650 may then provide the ability to detect the presence of foreign objects, thus allowing remedial action to protect the system 600 from damage caused by the presence of foreign objects. The information of the sensors 650 may also be used to alert users and operators of the system to the presence of a hazard (e.g., on the coils 714 or in the roadway 625) and maximize the efficiency of the deployed wireless

power transfer system

500, 600.

Fig. 6B is a functional block diagram of a sensor of the wireless power transfer system 600, according to an example embodiment. As shown, the sensor 650 is the same as that shown in fig. 6A. In one embodiment, sensor 650 may include sensor circuitry 665 for sensing conditions surrounding sensor 650, e.g., environmental conditions as discussed above with respect to fig. 6A. The sensor 650 further includes a memory 660 operatively coupled to the sensor circuitry 655, the memory 660 configured to store information derived from the sensor circuitry 655 regarding the detection of ambient conditions. The memory 660 may be further configured to store code (such as an operating system), or a database used to classify certain environmental characteristics detected by the sensor circuit 655.

The sensor 650 may further include a controller circuit 675 operatively coupled to the sensor circuit 655 and the memory 660. The controller circuit 675 can be substantially similar to the controller circuits 628, 638 (fig. 6A) and configured to receive certain sensed information from the sensor circuit 655 and can process the sensed information using information stored in the memory 660.

The sensor 650 further includes communication circuitry 670 operatively coupled to the controller circuitry 675. The controller circuit 675 may further transmit information to the communication circuit 629, the communication circuit 670 of the other sensor 650, the vehicle 505, or other possible recipients as mentioned with respect to fig. 6A, using the communication circuit 670.

The sensor 650 further includes a receive coil 665, the receive coil 665 operatively coupled to the controller 675, the sensor circuitry 655, the memory 660, and the communication circuitry 670. The receive coil 665 is substantially similar to the receive coil 614 and is configured to receive wireless power from the wireless field 605 (fig. 6A). Although not shown in this figure, receiver coil 665 may provide rectified, conditioned, and filtered power for powering various internal components of sensor 650, similar to the discussion of fig. 3 above. The sensor 650 may further include a power storage device 667 operatively coupled to the receive coil 665. The power storage device 667 can receive power from the receive coil 665 and be charged by the receive coil 665. The power storage device 667 can further power the sensor circuit 655, the controller circuit 675, the communication circuit 670, and the memory 660 when power is not available from the receive coil 665.

In one embodiment, the controller circuit 675 may process detection information from the sensor circuit 655 to allow the sensor 650 to transmit a foreign object detection message to the transmitter to indicate the presence of a foreign object. In another embodiment, the controller circuit 675 may transmit certain detection information related to conditions surrounding the sensor circuit 655 to an intended recipient via the communication circuit without processing the detection information.

Fig. 7A is a side view of a wireless power transfer system 700 with multiple sensors, according to an example embodiment. The system 700 is shown installed in a roadway ("roadway") 702. The system 700 may be employed in other similar ground surfaces (e.g., garages, parking lots, etc.) without departing from the spirit of the present disclosure. The system 700 may be employed as depicted in the previous figures, such as the stationary wireless power transfer system 400 (fig. 4) or as employed in the dynamic wireless charging system 500 (fig. 5).

System 700 is shown with a primary charging pad 704 similar to transmitter 604 of fig. 6A, mounted below the surface of roadway 702 at a distance 706 and surrounded by a plurality of sensors 710. The sensor 710 may be one of the various embodiments of the sensor 650 discussed with respect to fig. 6A, and may be distributed in a network or array as mentioned above. For simplicity, a single primary charging pad 704 is shown in the system 700; however, the plurality of pads 704 may be placed in sequence as shown in fig. 5 with respect to the dynamic wireless charging system 500. The individual components of the primary charging pad 704 may correspond to the individual components of the transmitter 604 of fig. 6A, however, for simplicity and brevity, not all of the components will be repeated here.

The sensors 710 may be mounted in various locations or arrangements around the primary charging pad 704. The

sensors

710a, 710b are shown mounted on top of the road surface. Sensor 710c is shown mounted within roadway 702 flush with the surface of roadway 702, while sensor 710d is shown mounted within the surface of roadway 702 but partially exposed above roadway 702. As discussed below with respect to fig. 7B, the sensor 710 may be further positioned on top of or next to the primary charging pad 704. The location of each sensor 710 may be based on the type, sensitivity, and/or capabilities of the implemented sensor 710. As mentioned below, the placement of the sensor 710 may be further influenced by the power output of the primary charging pad 704 (similar to the transmitter 604) at various locations around the primary charging pad 704 as well as the number and arrangement of antennas employed (e.g., transmit coils 614).

In one embodiment,

sensors

710a, 710b mounted above the surface of the roadway 702 may have the capability to include cameras (e.g., IR, or standard imaging cameras) or radar transceivers (e.g., millimeter wave, LIDAR) that are capable of detection or viewing in the horizontal plane and parallel to the surface of the roadway 702. Conversely, a sensor 710d installed in a roadway or a sensor 710c installed flush with the surface of a roadway may be limited in its ability to view or detect anything in a horizontal plane. Thus, such sensors may be limited to thermistors, humidity, pressure, or similar directional or non-directional sensors. However, it should be appreciated that virtually any sensor may be installed within or on top of the roadway as needed to provide a given capability.

The primary charging pad 704 may have integrated FOD capabilities, such as embedded FOD sensor(s) 712 (shown in phantom), however due to the mounting location of the primary charging pad 704 below the surface of the roadway 702, the FOD sensor 712 may not be able to provide sufficient FOD capabilities due to adverse effects from the distance 706 installed below the surface of the roadway 702 and/or due to effects of the composition of the roadway (e.g., concrete, asphalt). Thus, the sensor 710 may be appropriately positioned based on the following requirements: the already existing FOD capability (e.g., FOD detection range) of the primary charging pad 704 with the integrated FOD sensor 712 is improved or maximized. Sensor 710 can further provide additional FOD capabilities to system 700 that is not equipped with an integrated FOD system.

Similar to sensor 650 mentioned above in fig. 6A, sensor 710 may be powered by a wireless charging field (e.g., wireless field 605) and/or a wired connection, such as wired link 654 (fig. 6A) in the case of sensor 710 d. Similar to the above, sensor 710d is shown with a wired connection 720d similar to wired link 654 (fig. 6A).

The

sensors

710a, 710b, 710c are each shown with a wireless communication link 720a-720c, respectively, with the primary charging pad 704. Although "field lines" similar to the field lines of the wireless field 605 as shown in fig. 6A are not shown here for simplicity, the wireless communication links 720a-720c may be similar to the wireless field 605 and may also represent communication with the main charging pad 704 (e.g., communication link 652 of fig. 6A).

Similar to fig. 6A, the communication link 720 may provide the sensors 710 with communication capabilities to alert the controller 628 of the primary charging pad 704 of the presence of foreign objects 714, or to provide some other desired information depending on the capabilities of each of the sensors 710. In particular, the sensors may provide FOD information including temperature, humidity, traffic information, road conditions, etc., among other useful information. In one embodiment, such communication to the system 700 may alert a controller (e.g., controller 628) to take remedial action, command a reduction in power output by the primary charging pad 704 or complete deactivation when the foreign object 714 is present. As mentioned above, other useful communications related to environmental, weather, and/or traffic information may be made available to vehicles on the road (e.g., electric vehicle 505) via short-range communications or other network or tunneled communications.

Similar to the sensors 650a-650c (FIG. 6A), the sensors 710a-710c with wireless communication links 720a-720c may further receive wireless power from the primary charging pad 704. The amount and efficiency of power transfer from the primary charging pad 704 to each of the sensors 710a-710c may be affected by the location of the individual sensor 710 and the distance from the near field (e.g., the wireless field 605) of the primary charging pad 704.

In particular, the wireless field 605 may decrease in power with range. In one embodiment, the wireless field 605 may decrease exponentially with distance from the source (e.g., coil 614). As such, the distance between each wireless sensor 710a-710c and the primary charging pad 704 may be a factor in the design of the sensor 710 network. In one embodiment, the wireless field 605 may be "low" (e.g., low power measurement or weak field) in order to minimize possible damage to the integrated electronics within each of the sensors 710. However, the wireless field 605 may also need to be "high" (e.g., powerful) enough to allow for sufficient power transfer to the particular wireless sensor 710a-710 c. Accordingly, the optimal distance or range between the sensors 710a-710c and the primary charging pad 704 may be defined by a given design based on the specific network architecture, transmit field shape, power level, and/or resonant frequency of a given wireless field 605 as mentioned above with respect to fig. 6A. In one embodiment, the distance between the wireless sensor 710 and the primary charging pad 704 may be several centimeters (cm). For example, to provide sufficient wireless power, the sensor 710 may be located within five (5) to 50cm of the edge of the primary charging pad 704. In some embodiments, the sensor 710 may be positioned as far as one meter (1m) from the primary charging pad, with the transmitter 604 and transmitter coil 614 configured with larger dimensions and sufficient transmit power.

Similar to the discussion above with respect to fig. 5, the primary charging pad 704 may be required to activate and deactivate charging operations based on the presence of the vehicle 505 or other commands from the controller 628. In one embodiment, wireless power may therefore not always be available to wireless sensors 710a-710 c. This situation may present a hazard if the sensor 710 is not powered and the foreign object 714 is not detected.

Thus, without suffering damage to the individual sensors 710, the sensors 710 may operate at a minimum power state or minimum power level (e.g., zero to five percent of nominal) up to a maximum rated Inductive Power Transfer (IPT) power output during a charging operation. The design of sensor 710, along with appropriate magnetic or electrical shielding, may be used to avoid or minimize damage to sensor 710 or saturation of sensor 710, which may otherwise degrade the performance of sensor 710.

In one embodiment, the network of sensors 710 may include at least one sensor 710d having a wired connection 720d, the wired connection 720d may power the sensor 710d and provide FOD capability when the coil 614 or primary charging pad 704 is deactivated. Alternatively, the sensor 710 may further include a power storage device (e.g., a battery or capacitor — not shown), so the sensor(s) 710 are able to maintain a minimum power state and detect an object (e.g., foreign object 714) even when the power emitted by the primary charging pad 704 (e.g., the wireless field 605) is not present.

In one embodiment, power storage may not be limited to only wireless sensors 710a-710 c. When the primary charging pad 704 is deactivated, the sensor 710 with the wired connection 720d may also be deactivated, so additional power storage devices (such as the noted batteries or capacitors) may also be beneficial if included in the wired sensor 710 d. In both cases, the sensor 710 may continue to provide FOD capabilities to the system 700 while the primary charging pad 704 is deactivated (e.g., powered off). This may allow the sensor 710 to provide an adequate alert when a foreign object 714 is present and prevent the system from beginning a charging operation.

In one embodiment, the use of multiple or switched transmit coils 614 within the primary charging pad 704 may also be implemented to minimize damage to the sensor 710. For example, the primary charging pad 704 may include two separate coils (not shown). Such an embodiment may include a larger coil 614 for low power environments, and a smaller coil 614 for full power. This may provide reduced power consumption to the overall system 700 while maintaining FOD capability by continuously providing wireless power to each sensor 710.

In one embodiment, the primary charging pad 704 may conserve power by regulating the power output to a low power setting or by completely powering down. As such, the sensor 710 may also enter a "sleep mode" if wireless power is not available or to conserve battery power. In one embodiment, the sensor 710 may also include a "wake up" function that activates the sensor 710 when partial power is available from the primary charging pad 704 during activation of the charging operation. This may be incorporated into the sensor 710 with or without an integrated power storage device. This may further provide minimal power consumption beyond normal charging operation once the primary charging pad 704 begins wireless power transfer, while providing full FOD capability. Such an embodiment may be able to detect a foreign object (e.g., foreign object 714) after power is turned on but before the primary charging pad 704 reaches full power.

In another embodiment, several switchable antennas (e.g., multiple transmit coils 614) can be positioned such that reception of the wireless field 605 (e.g., magnetic or electric field) is optimized for a particular implementation and/or aligned for a low power environment. Further, the switchable antenna (e.g., the plurality of transmit coils 614) may also be positioned (e.g., misaligned) such that the wireless field 605 is reduced for high power environments. Such an architecture may provide additional options for maintaining FOD capability and wirelessly powering the sensors 710a-710c during charging operations when the primary charging pad 704 is at full power. This may also provide a way to avoid damaging or saturating individual sensors 710 by placing sensors 710 in specific "low power" regions of field 605. Accordingly, the placement and design of the sensors 710 may specify a specific placement location for each sensor 710 such that each sensor is placed to maximize or optimize power delivery and foreign object 714 detection capabilities.

Fig. 7B is a top view of the wireless power transfer system of fig. 7A, according to an example embodiment. As shown, the sensors 710 are distributed in various locations around the primary charging pad 704 similar to that of fig. 7A.

Integrated sensor 712 is shown in dashed lines indicating its location below the surface of roadway 702 and within primary charging pad 704. As discussed with respect to fig. 7A, sensors 710a-710c are placed around the primary charging pad with wireless communication links 720a-720c, respectively, with the primary charging pad 704. Sensor 710d is shown having a wired connection 720d with the primary charging pad 704, positioned within the surface of the roadway 702 (as shown in fig. 7A) and above the primary charging pad 704. The location of the sensor 710 can be used to increase both the detection range and resolution of the FOD capability of the system 700, while improving the capability of the integrated FOD sensor 712 (if installed). The specific location of the individual sensors 710 may be based on the strength of the wireless field 605 in a particular location around the primary charging pad 704, and thus the ability of a given sensor 710 to receive wireless power. The placement of the sensor 710 may also vary based on the installed depth of the primary charging pad (e.g., distance 706) if installed below the surface of the roadway 702.

The foreign object 714 is shown in close proximity to the primary charging pad 704, closest to the

sensors

710c, 710 d. In one embodiment, when the primary charging pad 704 begins to generate the full power wireless field 605 for the wireless charging operation, the metallic foreign object 704 may absorb the emitted energy. Foreign object 714 is depicted as a wrench, which may have a metal composition, but other foreign objects 714 may be any debris in the installation area (e.g., roadway 702, roadway 525 of fig. 5) or in the parking area (such as the parking area shown in fig. 4). When the power of the wireless field 605 is absorbed by the foreign object 714, it may rise in temperature with a heating hazard. Foreign object 714 may further pose a hazard to vehicle 605 if found in

roads

702, 525.

When one or more of the sensors 710 detect the foreign object 714, the sensors 710 may relay information related to the detection (e.g., elevated temperature, thermal imagery, light data, etc.) to the controller 628 via the communication circuitry 629 in order to take appropriate action to adjust the power output of the emitters 604, notify an operator of the system 700, and/or take other action as appropriate. Inter-sensor communication 656 (also shown in fig. 6A) may further be available to relay information from one sensor to another. Referring briefly to FIG. 6A, inter-sensor communications 656A-656b are shown, indicating inter-sensor communications between

sensors

710a, 710b and between

sensors

710b, 710 c. In fig. 7, inter-sensor communication 656c is also depicted, illustrating inter-sensor communication between wireless sensor 710c and wired sensor 710 d. As such, the sensor 710d may be further configured to communicate wirelessly with other sensors 710 or the primary charging pad 704. As mentioned above, such information may be relayed to other sensors 710, the primary charging pad 704, the vehicle 605, or other wireless charging system 700, enabling transmission of sensor 710 information.

Fig. 8 illustrates a flow chart depicting a method 800 of providing wireless power to the sensors of fig. 7A and 7B, according to an example embodiment. The method illustrated in fig. 8 may be implemented via one or more of the devices in a controller substantially similar to the control circuit 628 of the wireless charging system including the primary charging pad 704 of fig. 7A-7B and the transmitter 604 of fig. 6A. Method 800 may be performed in conjunction with at least one sensor or sensor network, such as sensor 650 of fig. 6A or sensor 710 of fig. 7. In one embodiment, the controller 628 may command activation or deactivation of a wireless field substantially similar to the wireless field 605 (FIG. 6A) that provides wireless power to the sensors. Once power is delivered to the one or more sensors, the wireless field may further provide power to an electric vehicle (such as vehicle 505 of fig. 5, or vehicle 605 of fig. 6A). If a foreign object is detected by one or more of the sensors, the controller may receive a detection signal from the sensor and command a reduction in wireless field transmission power or a complete shutdown as required.

The process 800 begins at block 810, where the controller 628 may command activation of a wireless charging pad, such as the primary charging pad 704 (fig. 7) or the base pad 415 (fig. 4), that provides wireless power to at least one sensor. The sensor may then be able to monitor the surrounding area for the presence of foreign objects or other environmental conditions as desired.

At block 820, the charging pad may further provide wireless power to the electric vehicle. In one embodiment, the vehicle may be proximate to a charging base pad (such as 515 (fig. 5)), at which point a proximity sensor (such as proximity sensor 510 of fig. 5) may indicate the presence of the vehicle 505 to the controller 628. In response, the controller 628 may then command an increase in the power output of a transmitter of the charge pad, such as the transmitter 604 (fig. 6A), to cause sufficient wireless power to be delivered to the vehicle and the wireless sensor.

At block 830, the controller 628 may monitor at least one of the sensors 710 (fig. 7A-7B) for an appropriate indication based on the capabilities of the individual sensors 710. In one embodiment, the sensors may wirelessly transmit sensor information to the controller 628 or to other sensors 710 via a wireless link, such as wireless links 720a-720c (FIGS. 7A-7B), or transmit sensor information to the controller 628 via a wired link 720d (FIGS. 7A-7B). The controller 628 may continuously monitor the sensors 710, periodically poll each of the sensors 710, or the controller 628 may periodically or continuously receive independently transmitted information from each of the sensors 710.

At decision block 840, the controller 628 may determine whether the sensor has detected foreign matter based on information received from the at least one foreign matter sensor 710. As a non-limiting example, an abnormally high temperature at sensor 710 may indicate detection of a foreign object. In one embodiment, abnormally high temperatures may be localized at a single foreign object sensor 710 due to absorption of energy from the wireless field 605, which indicates the presence of a foreign object 714 (fig. 7A-7B). In another embodiment, a thermal camera or imaging camera may indicate or verify the presence of foreign object 714. In one embodiment, the controller 628 may determine detection based on the indications and data received from the sensors 710. In another embodiment, certain detection processes may be distributed to the sensor 710, whereby the sensor 710 may send a detection signal to the controller 628.

At block 850, when a foreign object detection signal is sent from the sensor to the controller 628, the controller may command an adjustment to the power output of the transmitter 604 to reduce or deactivate the wireless field 605. Process 800 may end after the wireless power level adjustment.

If no foreign object is detected at decision block 840, the controller 628 may continue to receive and consider sensor information (e.g., temperature, humidity, road conditions, camera images, etc.) from the at least one sensor 710. In one embodiment, the sensor information may be further used by the controller 628 to command power adjustments, or the information may be forwarded to other wireless charging systems 700 (fig. 7), or to the vehicle 505.

At block 890, because no foreign object is detected, the process 800 will continue wireless power delivery to the vehicle, returning the process 800 to block 820.

FIG. 9 illustrates a flowchart depicting a method 900 of operating one or more of the sensors 710 (FIGS. 7A-7B) according to an exemplary embodiment.

The method 900 may be implemented via one or more of the sensors substantially similar to the sensor 710 (or network of sensors 710) of the wireless charging system including the primary charging pad 704 of fig. 7A-7B and the transmitter 604 of fig. 6A. The method 900 may be performed in conjunction with a controller (such as the control circuit 628 of fig. 6A). In one embodiment, at least one of the sensors 710 may receive wireless power from a primary charging pad that is substantially similar to the primary charging pad 704. As discussed below, once power is delivered to one or more sensors, the sensor 710 may monitor the surrounding environment for certain changes or for indications of the presence of foreign objects and report such indications to the controller 628 for an appropriate response.

The process 900 begins at block 910, where at least one sensor 710 receives wireless power from the primary charging pad 704.

At step 920, the sensor 710 may detect an environmental condition based on the sensor 710 capabilities. As non-limiting examples, some sensors 710 may only detect temperature changes, while other sensors 710 may provide imaging (e.g., color or thermal imagery), humidity data, or traffic conditions, among many other possibilities.

At block 930, the sensor may monitor the environment for foreign matter, such as foreign matter 714 (fig. 7A-7B). In one embodiment, the sensor 710 may report only indications to the controller 628 based on sensor capabilities. In certain embodiments, the sensor 710 may be configured to independently detect and report the presence of foreign objects to the controller 628.

If a foreign object 714 is detected at decision block 940, the sensor 710 may send a foreign object detection warning to the primary charging pad 704 (or more particularly the controller 628). The sensor 710 may then continue to detect the environmental condition at block 920.

If no foreign object is detected at decision block 940, the sensor 710 may transmit sensor information to the primary charging pad 704, other sensors 710, and/or the vehicle 605 at block 940 to make the detection information available to other systems and users.

Claims

1. An apparatus for detecting a condition within a wireless charging field, the apparatus comprising:

a wireless power receiver configured to receive wireless charging power from a wireless power charging transmitter;

a first sensor circuit disposed at least partially within a ground surface, the first sensor circuit operatively coupled to and configured to be charged or powered by the wireless power receiver and further configured to detect the condition; and

a controller circuit operatively coupled to the first sensor circuit and the wireless power receiver, the controller circuit configured to communicate the detected condition or transmit a shutdown command to the wireless power charging transmitter via a communication circuit in response to the detected condition.

2. The apparatus of claim 1, wherein the first sensor circuit is further configured to cause the wireless power charging transmitter to adjust a transmitted power level of the wireless power charging transmitter or to disable wireless power charging in response to the detected condition.

3. The apparatus of claim 1, wherein the condition detected comprises at least one of: the presence of foreign objects, changes in magnetic fields, measurement of temperature, measurement of humidity, measurement of air pollution, and measurement of traffic density.

4. The apparatus of claim 1, wherein the first sensor circuit is further configured to transmit information to an electric vehicle related to the detected condition, the information indicating a degraded operating mode of the wireless power charging transmitter or a ground or road alert.

5. The apparatus of claim 1, wherein the first sensor circuit is further configured to communicate information between a second sensor circuit and the wireless charging transmitter, between the wireless charging transmitter and a first vehicle, and between the first vehicle and a second vehicle.

6. The apparatus of claim 1, further comprising:

a power storage device operatively coupled to the wireless power receiver and the first sensor circuit, the power storage device configured to:

receiving wireless charging power from the wireless power receiver while the wireless power charging transmitter is at a first power level, an

Powering the first sensor circuit when the wireless power charging transmitter is at a second power level, the second power level being lower than the first power level.

7. The apparatus of claim 1, wherein the first sensor circuit is further configured to be charged or powered by power received from a power storage device or power received from the wireless power receiver when the wireless power charging transmitter is transmitting power at a power level insufficient to charge a vehicle and sufficient to charge or power the wireless receiver.

8. The apparatus of claim 1, wherein the first sensor circuit is further configured to communicate information related to the detected condition to a second sensor circuit configured to communicate the detected condition to the wireless power transmitter.

9. The apparatus of claim 1, wherein the first sensor circuit is further configured to detect a presence or absence of a vehicle within an area of the first sensor circuit and to communicate information related to the presence or absence of the vehicle to a controller, the controller configured to determine a traffic condition based on the information from the first sensor circuit and information from a second sensor circuit related to the presence or absence of another vehicle in the area of the second sensor circuit.

10. A method for detecting a condition within a wireless charging field, the method comprising:

receiving, at a wireless power receiver, wireless charging power from a wireless power charging transmitter;

detecting the condition at a first sensor circuit, the first sensor circuit being at least partially disposed within a ground surface, operatively coupled to, and charged or powered by, the wireless power receiver; and

in response to the detected condition, communicating the detected condition or transmitting a shutdown command to the wireless power charging transmitter.

11. The method of claim 10, further comprising:

adjusting a transmitted power level of the wireless power charging transmitter or disabling wireless power charging in response to the detected condition.

12. The method of claim 10, wherein detecting the condition comprises detecting at least one of: the presence of foreign objects, changes in magnetic fields, measurement of temperature, measurement of humidity, measurement of air pollution, and measurement of traffic density.

13. The method of claim 10, further comprising:

transmitting information to an electric vehicle related to the detected condition, the information indicating a degraded mode of operation of the wireless charging transmitter or a ground or road alert.

14. The method of claim 10, further comprising:

communicating information related to the detected condition from a second sensor circuit to the wireless charging transmitter, from the wireless charging transmitter to a first vehicle, and from the first vehicle to a second vehicle via the first sensor circuit.

15. The method of claim 10, further comprising:

receiving wireless charging power from the wireless power receiver at a power storage device when the wireless power charging transmitter is at a first power level, the power storage device operatively coupled to the wireless power receiver and the first sensor circuit; and

powering the first sensor circuit with the power storage device while the wireless power charging transmitter is at a second power level, the second power level being lower than the first power level.

16. The method of claim 10, further comprising:

charging or powering the first sensor circuit with power received from a power storage device or power received from the wireless power receiver while the wireless power charging transmitter is transmitting power at a power level that is insufficient to charge a vehicle and sufficient to charge or power the wireless receiver.

17. The method of claim 10, further comprising:

communicating information related to the detected condition from the first sensor circuit to a second sensor circuit configured to communicate the detected condition to the wireless power transmitter.

18. The method of claim 10, further comprising:

detecting a presence or absence of a vehicle within a region of the first sensor circuit; and

communicating information relating to the presence or absence of the vehicle to a controller, the controller configured to determine a traffic condition based on the first sensor circuit information and second sensor circuit information relating to the presence or absence of another vehicle in the area of a second sensor circuit.

19. An apparatus for detecting a condition within a wireless charging field, the apparatus comprising:

means for receiving wireless charging power from a wireless power charging transmitter;

a first means for detecting the condition, the first means for detecting being at least partially disposed within a ground surface and operatively coupled to and charged or powered by the means for receiving; and

means for controlling the first means for detecting and the means for receiving, the means for controlling configured to communicate the detected condition or transmit a shutdown command to means for providing wireless charging power via a communication circuit in response to the detected condition.

20. The apparatus of claim 19, wherein the means for receiving comprises a wireless power receiver, and wherein the first means for detecting comprises a first sensor circuit.

21. The apparatus of claim 19, wherein the first means for detecting is further configured to cause the wireless power charging transmitter to adjust a transmitted power level of the wireless power charging transmitter or to disable wireless power charging in response to the detected condition.

22. The apparatus of claim 19, further comprising:

means for storing power operatively coupled to the means for receiving and the first means for detecting, wherein the power storing means is configured to receive wireless charging power from the means for receiving when the wireless power charging transmitter is at a first power level, and wherein the power storing means is further configured to power the first means for detecting when the wireless power charging transmitter is at a second power level, the second power level being lower than the first power level.

23. An apparatus for providing wireless power, comprising:

a wireless power transmitter configured to provide wireless power to the first sensor; and

a first controller configured to receive information from the first sensor, the information indicating a presence of a foreign object, the first controller further configured to reduce power transmitted from the wireless power transmitter to an electric vehicle in response to the information,

wherein the first controller is further configured to receive information relating to the presence or absence of a vehicle within the area of the first sensor, and wherein the first controller is further configured to determine a traffic condition based on the information from the first sensor and information from a second sensor relating to the presence or absence of another vehicle in the area of the second sensor.

24. The apparatus of claim 23, wherein the information comprises information relating to at least one of: the presence of foreign objects, changes in magnetic fields, measurement of temperature, measurement of humidity, measurement of air pollution, and measurement of traffic density.

25. The apparatus of claim 23, wherein the first controller is further configured to communicate the information from the first sensor to at least one of the electric vehicle, a second controller, and an infrastructure network.

26. The apparatus of claim 23, wherein the wireless power transmitter is further configured to provide wireless power at a first power level sufficient to wirelessly power an electric vehicle and the first sensor, and a second power level sufficient to wirelessly power the first sensor, the second power level being lower than the first power level, and wherein the second power level is insufficient to power the electric vehicle.